I am looking for any recommendations or suggestion for Ground Planes for two different grounds
I am designing a battery powered device with two voltage sources, 1 coming from the AC wall and other from a Li-ion battery when there is not energy available from the AC wall.
in the PCB design state I am facing a concern about the ground planes because it is very important for the design (reduce heat, impedance control, EMI) so I added a gas gauge to monitoring my battery state, but it requires a Rsense from the battery to my load. my question is now I have "two" different Ground separates for a miliOhm resistor, on stage for my DC-DC input converter and the other for the Battery to the load. is it right? how can I can handle the ground planes if one is "isolate" for a mOhm resistor.
should I keep my two different ground loops as small as possible?
Details: input 9V Load 5v/5A battery 3.7v (high current 15A max)
any recommendation for monitoring the current in a different way? or any battery charger IC with gas gauge feature? Thanks